Its hard to say if we´re missing out, because we naturally are compelled to enjoy different things. So, we really truly say that we´re missing out, because we don´t like most of that stuff anyway. It´s like asking the person who is a die-hard fan of football if he´s "missing out" on loving baseball.
On another note, possibly contradicting what I just said, I do think that at first we are missing out. Missing out on friendships, relationships, experiences. But, in the end we gain more. A lot more than others can imagine once we figure everything out, and actually gain those friendships and relationships. Its hard to appreciate something that you´ve always had.
I remember reading an article once about a boy who escaped the genocide in Africa many years ago and came to America. They asked him something along the lines of, "aren´t you sad right now because of everything that you´ve been through?". And, he gave a reply which I don´t think that I´ll ever forget, which went something like, "sad? how could I possibly be sad? I have a roof over my head, I am out of a war zone, and I have three square meals every day. I could not be happier." This made me realize that here is a person who will always appreciate that which I have had for my whole life, infinitely more than I can ever imagine. I will never be able to appreciate three meals a day like him, nor a roof over my head like him. I can "appreciate" them, but never appreciate them like he will.
This is what I think that relationships and friendships for us is like later in life. Other people will never appreciate them as much as we will, nor will it ever be possible for them to understand how much we appreciate such things. Because these are things they have always had, and you just can´t appreciate something you´ve always had like the person who has never had them. Yes, its hard at first, almost impossible. Some of us don´t make it to see the day. But, maybe, just maybe, if you can hold on long enough to make it, you can find happiness that others can never imagine.
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Only a miracle can save me; too bad I don't believe in miracles.